2
The Anatomy of Crashes Involving Young Drivers

An understanding of how the number of teen crashes might be reduced begins with an understanding of how they happen. Many of the speakers presented data that shed light not only on the strikingly large scope of the problem, but also on what goes wrong when teenagers have crashes.

THE GRAVEST PUBLIC HEALTH PROBLEMFOR YOUNG DRIVERS

Driving is dangerous, and especially so for new drivers. Motor vehicle crashes are the leading cause of mortality and serious morbidity for all young people ages 4 through 34, and the rates are highest during new drivers’ first few months of driving on their own. In fact, during their first six months of solo driving, newly licensed drivers are about eight times more likely to be involved in fatal crashes than are more experienced drivers (Insurance Institute for Highway Safety, 2004). Even after more than six months licensed to drive alone, teens are two to three times more likely to be in a fatal crash than are the most experienced drivers. The overall numbers are alarming— by one analysis, more than 100,000 young people (ages 16 to 24) will die in vehicle crashes between 2003 and 2012 if the crash rates do not change, as shown in Table 2-1.

Crash rates are significantly higher for male than female drivers, but while overall rates are increasing, young women are catching up with young

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2
The Anatomy of Crashes
Involving Young Drivers
A
n understanding of how the number of teen crashes might be re-
duced begins with an understanding of how they happen. Many of
the speakers presented data that shed light not only on the strik-
ingly large scope of the problem, but also on what goes wrong when teen-
agers have crashes.
THE GRAVEST PUBLIC HEALTH PROBLEM
FOR YOUNG DRIVERS
Driving is dangerous, and especially so for new drivers. Motor vehicle
crashes are the leading cause of mortality and serious morbidity for all young
people ages 4 through 34, and the rates are highest during new drivers’ first
few months of driving on their own. In fact, during their first six months of
solo driving, newly licensed drivers are about eight times more likely to be
involved in fatal crashes than are more experienced drivers (Insurance Insti-
tute for Highway Safety, 2004). Even after more than six months licensed
to drive alone, teens are two to three times more likely to be in a fatal crash
than are the most experienced drivers. The overall numbers are alarming—
by one analysis, more than 100,000 young people (ages 16 to 24) will die
in vehicle crashes between 2003 and 2012 if the crash rates do not change,
as shown in Table 2-1.
Crash rates are significantly higher for male than female drivers, but
while overall rates are increasing, young women are catching up with young
6

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7
THE ANATOMY OF CRASHES INVOLVING YOUNG DRIVERS
TABLE 2-1 Cumulative Total Deaths from Motor
Vehicle Crashes Involving Teen Drivers, 2003 to 2012
Projected Cumulative
Age Group Number of Deaths
16 to 17 20, 896
18 to 19 27, 689
20 to 24 54, 830
Total 103, 415
NOTE: Analysis based on calculations from the Fatality Analysis
Reporting System, 2003 data.
SOURCE: Winston (2006).
men. Moreover, the proportionate mortality rates—that is, the number of
vehicle crash deaths divided by the number of all deaths among 16- to 19-
year-olds—are 36.5 percent for young men and 46.5 percent for young
women (D’Angelo, 2006). The high mortality rates for young drivers (ages
15 to 20) have persisted over the past decade, with an increase of 5 percent
between 1994 and 2004. During this same time period, driver fatalities
rose by 1 percent among young male drivers, compared with a 15 percent
increase for young women, according to data presented by Richard
Compton (National Highway Traffic Safety Administration, 2006a).
Injuries are another significant component of the problem—303,000
young people ages 15 to 20 were injured in crashes in 2004, many of them
very seriously (National Highway Traffic Safety Administration, 2006a).
Moreover, these numbers do not include deaths or injuries of thousands of
other nonteenage drivers, passengers, or pedestrians that occur as a result of
crashes caused by teenage drivers (American Automobile Association,
2006).
From a public health perspective, motor vehicle crashes are among the
most serious problems facing teenagers. Studies by the AAA Foundation
for Traffic Safety indicate that teen drivers are overrepresented in road
crashes, with a higher per-mile collision rate than older drivers (American
Automobile Association, 2006). From an economic perspective, these
crashes also impose an enormous cost to society. It is estimated by the
Centers for Disease Control and Prevention that the 2002 cost of crashes
involving drivers ages 15 to 20 was $40.8 billion (National Center for In-
jury Prevention and Control, 2006). This information can provide a useful

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8 PREVENTING TEEN MOTOR CRASHES
context for discussions of the costs of measures designed to reduce the
number of teen crashes.
RISK FACTORS
Just what is it about teenagers that makes them prone to motor vehicle
crashes? Jim Hedlund provided a framework for the wealth of data on risk
factors for teens by describing five critical elements teens need to drive
safely:
• skills—which include the capacity to operate the vehicle and to rec-
ognize hazards, as well as the capacity to react appropriately to the unex-
pected;
• knowledge—of traffic rules and operating procedures, as well as
understanding of risks and their potential consequences;
• experience—including both sufficient practice, as well as the famil-
iarity with the consequences of bad judgment that fosters good judgment;
• maturity—or developed capacity for reasoning, judgment, and de-
cision making; and
• environment—or safe surroundings in which to learn to drive.
Whether or not these elements are all in place, teens are eager to drive,
and their crash risk is particularly high in the first few months they are on
the road, as well as when they travel at night, when teenage passengers are
in the car, when they are driving too fast for conditions, and when they
have consumed alcohol. Parents often believe that if they could be sure
their teenagers would never drink and drive, or ride with someone else who
had been drinking, their children would be safe on the road, but, as David
Preusser noted, the biggest risk factor for teens is possession of a driver’s
license. The key reasons why are discussed below.
Youth
Young drivers are at significantly higher risk than older drivers, as we
have seen, and there is a learning curve for all new drivers, regardless of the
age at which they begin driving.1 Table 2-2 shows the steep decline in crash
1So-called recalcitrant high-risk drivers, those who are characterized by disregard for
authority and a propensity for risk-taking beyond the teen years, have also been identified as

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THE ANATOMY OF CRASHES INVOLVING YOUNG DRIVERS
TABLE 2-2 Crash Rates for Novice Drivers per Cumulative Miles
Driven After Licensure
Miles Driven Crash Involvement Rate
After Licensure (per 10K cumulative miles)
250 3.2 average for all drivers
3.4 for males
3.1 for females
500 1.8 average for all drivers
1.7 for males
2.0 females
750 1.3 average for all drivers
1.0 for males
1.8 for females
NOTE: For novice drivers, crash rates decrease dramatically from the 1st to the 7th
month (41 percent), then gradually decrease through the 24th month after licensing
(60 percent overall reduction) (Mayhew, Simpson, and Pak, 2003).
SOURCE: Reprinted, with permission, from McCartt et al. (2003). Copyright 2003
by Elsevier.
rates for both male and female newly licensed drivers as they accumulate
miles of practice. Other research provides even more detail, showing that
crash rates are highest during the first 250 miles of driving (3.2 crashes per
10,000 miles) and the second 250 miles (2.0 per 10,000 miles). After this
introductory period, the crash rates decline sharply (McCartt et al., 2003).
Since few people in the United States learn to drive after their teen
years, data are not available in this country to allow comparison of the
experiences of younger and older novice drivers. Countries in which wait-
ing past the teen years to begin driving is more common, such as Canada
and New Zealand, have found that older novice drivers also have higher
a category. These adult drivers were not addressed at the workshop, but it is important to
note that some proportion of teenagers have characteristics that will place them in this group
once they are adults, and that the development of safe driving practices for this group may
pose challenges distinct from the teen driver problem.

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10 PREVENTING TEEN MOTOR CRASHES
9
8
7
6
Fatal Crash Rate
5
4
3
2
1
0
16/16-17 15.5/16 15/16 14/16 14-15/14-15
Learn Age/License Age
age 15 age 16 age 17
FIGURE 2-1 Driver fatal crash involvement rates (per 100,000 population, 1989-
1993).
NOTE: Each column represents different groups of states, classified by the variations
in ages at which practice driving (learn age) and licensure occurs, as catalogued by
Williams et al., 1995.
SOURCE: Preusser (2006). Data drawn from Preusser (1995).
crash rates during their initial years of driving than do their peers with
more driving experience. Nevertheless, there is evidence that even slight age
differences in the adolescent years may have some effect. Figure 2-1 shows
data suggesting that fatal crash rates are higher the younger the driver.
Possible reasons why waiting even 12 to 18 months beyond the once-
standard 16th birthday target for licensure may be beneficial are explored
in Chapter 3. However, the data on crash rates for young novice drivers are
sufficiently compelling that many states have adopted graduated driver li-
censure (GDL) programs, which both prolong the time it takes to become
fully licensed and provide for more training and supervised practice driving
during the learning period. Whether the benefits come from the licensing
of older adolescents, the delay itself (and consequent limitations on younger,
inexperienced drivers’ hours behind the wheel), or from the nature of the
experiences young drivers have during the longer waiting period, these pro-
grams, which are discussed in greater detail in Chapter 4, have shown sig-
nificant benefits. One study, for example, has reported an average 11 per-
cent reduction in fatal crashes among 16-year-olds who obtained their
licenses through GDL (Baker, Chen, and Guohua, 2006).

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11
THE ANATOMY OF CRASHES INVOLVING YOUNG DRIVERS
Inexperience
The newly licensed driver faces less favorable odds than does the more
experienced driver, and, as Don Fisher explained, a variety of studies sup-
port the conclusion that it is newly licensed drivers’ lack of experience that
is the most significant problem, even considering that the youngest drivers
fare the worst. For example, one analysis of police reports of almost 2,000
crashes in which newly licensed drivers were involved pointed to inexperi-
ence as the major contributor (McKnight and McKnight, 2003). These
findings are consistent with those of an earlier study (Treat et al., 1979) in
which ineffective visual search (scanning for hazards), speed adjustment,
and attention, in that order, were implicated as causes of newly licensed
driver crashes. Similarly, Gregersen (1996) estimated that some 70 percent
of novice driver errors were attributable to inexperience. The errors that are
typical of inexperienced drivers are discussed below.
Alcohol
Teens are especially vulnerable to the risks of drinking and driving.
Younger, newly licensed drivers, as a group, have comparatively few
alcohol-related crashes, while older, more experienced teen and young adult
drivers have more such crashes than do adults. Nevertheless, alcohol signifi-
cantly impairs driving capacity among all teenagers—and at lower blood
levels than typically affect adults. As Figure 2-2 shows, the risk of crashing
rises dramatically with blood alcohol content (BAC) at any age, and the
effects are more marked for drivers ages 16 to 20 than for those ages 35 to
49. While peaks in substance use typically occur slightly later in the teen
years (around ages 18 to 20) than driving usually begins, younger teens
certainly use alcohol. Moreover, some evidence suggests that adolescents’
physiological responses to alcohol may be different from those of adults,
and specifically that teens may be less sensitive to signals that they are im-
paired (National Research Council and Institute of Medicine, 2004, 2006).
The availability of alcohol clearly poses a risk to all teen drivers.2 A
total of 24 percent of drivers ages 15 to 20 who were involved in fatal
2Not discussed at the workshop but of vital importance is the question of how under-
age teens obtain alcohol and ways of reducing their access to it. These topics were addressed
in an earlier National Academies study on strategies to reduce underage drinking (National
Research Council and Institute of Medicine, 2004).

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12 PREVENTING TEEN MOTOR CRASHES
30
ages 16 -20
ages 35 -49
25
20
Crash Risk
15
10
5
0
00 01 02-03 04-05 06-07 08-09 10-14 15-19 20+
BAC
FIGURE 2-2 Crash risk by blood alcohol content (BAC).
SOURCE: Preusser (2006). Data drawn from Preusser (2002).
crashes in 2004 had a BAC of 0.08 or higher, and the percentage increased
from 17 percent for 15-year-olds to 34 percent for 20-year-olds (National
Highway Traffic Safety Administration, 2006b). Alcohol is much more
likely to play a role in fatal crashes involving young men (26 percent) than
young women (12 percent) in this age group. Crashes in which alcohol is
involved tend to be more severe, and persons involved in alcohol-related
crashes are less likely to be wearing seat belts. The National Highway Traf-
fic Safety Administration (NHTSA) reports that raising the minimum legal
age for drinking, which is now 21 in all states and the District of Colum-
bia, has saved many lives—906 just in 2004. These laws are discussed more
fully in Chapter 4.
Passengers
The risk of crashing is significantly elevated for teen drivers who have
teenage passengers, particularly male passengers, in the car, as Anne
McCartt and others made clear. Table 2-3 shows the association of passen-
gers and the already elevated crash risk for teen drivers—the figures for 16-

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THE ANATOMY OF CRASHES INVOLVING YOUNG DRIVERS
TABLE 2-3 Crash Risk by Driving Alone or with
Passengers, by Age of Driver
Driver Age Alone Passenger(s)
16 2.28 4.72
17 1.77 3.52
18 1.77 3.66
19 1.61 3.23
20-24 1.50 2.54
25-29 1.28 1.69
30-59 1.00 1.00
SOURCE: Reprinted, with permission, from Preusser et al.
(1998). Copyright 2003 by Elsevier.
year-olds are particularly striking, showing a risk of 2.28 for drivers alone
and 4.72 for drivers with any passengers, compared with 1.00 for drivers
ages 30 to 59, with or without passengers. Additional data presented by
McCartt (Table 2-4) demonstrate how the presence of multiple passengers
seems to magnify the risk of crashes, whether they are caused by driver
error, speeding, or alcohol consumption.
Bruce Simons-Morton offered support for the proposition that male
teen passengers have a significantly larger impact on risky driving behaviors
than do female passengers, although the reasons for this discrepancy are not
clearly understood. Data from a study of teen driver behavior show how
drivers with male passengers are likely to increase their speed and leave less
distance between their own and other vehicles. Conversely, this same study
indicates that the presence of female passengers frequently confers a protec-
tive effect for young drivers, both male and female.
Driving at Night
Although the majority of teen driver crashes occur during daylight
hours (when teens are more likely to be on the road), fatal crash rates per
miles driven are higher for teens driving at night than during the day. Night-
time conditions present significant challenges for all drivers, but the safety
gap between night and day narrows significantly between age 16 and ages
30 to 40.

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14 PREVENTING TEEN MOTOR CRASHES
TABLE 2-4 Fatal Crash Characteristics, 16-Year-Old Driver Alone or
with Teen Passengers (percentage)
Driver 1 Teen 2 Teen 3+ Teen
Alone Passenger Passengers Passengers
72a
Driver error 82 83 90
Speeding 30 45 50 59
Single vehicle 36 51 59 72
0.08+ blood alcohol level 9 8 10 12
aTotalsmay exceed 100% because crashes may involve more than one characteristic.
SOURCE: Insurance Institute for Highway Safety. Unpublished analysis of 2004 data
from the Fatality Analysis Reporting System, National Highway Traffic Safety
Administration.
Fatigue
Teen drivers who lack adequate sleep are also at higher risk of crashing.
Fatigue can interact with other risk factors (such as speed, alcohol, and
inexperience), and its role is underreported in crash data because it is not
readily apparent to investigators. As a result, its relative contribution is
difficult to study. Sleep deprivation may also play a role in nighttime
crashes, as discussed in Chapter 3.
COMMON TEEN DRIVING ERRORS
A look at the more immediate causes of young driver crashes, among
both newly licensed and more experienced drivers, provided another per-
spective on what can go wrong. James McKnight distinguished between
the physical skills involved in operating a vehicle, which are relatively easily
mastered, and the more complex capacities that are also necessary for safe
driving. Recognizing and correcting for errors and detecting hazards in the
roadway are key elements of driving safely, for example, and acquiring these
skills takes much longer than learning the mechanics of driving. Some of
the principal errors that teenagers make while driving include failure to:
• maintain attention and avoid distractions, including electronic de-
vices in the car;

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THE ANATOMY OF CRASHES INVOLVING YOUNG DRIVERS
• search ahead, such as before left turns;
• search to the side, such as when yielding the right of way at an
intersection;
• search to the rear, such as when changing lanes;
• adjust speed in response to traffic or road conditions;
• maintain space between their own and other vehicles, such as cor-
rect following distance;
• respond correctly to emergencies, such as recovering from a skid or
sudden swerve;
• maintain basic control of the vehicle, such as keeping within a lane,
braking, and turning smoothly;
• respond to traffic controls, such as traffic lights or guidance about
lane use; and
• avoid driving while impaired by alcohol or sleepiness or driving a
vehicle that needs repair.
McKnight offered a simplified summary of what teens need to learn to
become successful drivers: knowledge of the rules of the road, safe operating
procedures, and the consequences of not adhering to them; understanding
that what they know and do will affect their safety; and the skill to control
the car, handle an emergency, and recognize potential hazards in time to
avoid them. As the conversation turned to intervention strategies, partici-
pants repeatedly stressed that remedies need to address these three elements
in realistic ways. However, the information about risk factors and teen driver
error goes only so far in explaining teen crashes—it does not address the
reasons why teens often lack the critical elements. Thus, the workshop also
explored the nature of adolescents and the developmental processes that
they experience—with an eye to identifying ways in which this deeper
knowledge could be applied to the development of more effective educa-
tional programs and prevention strategies for teen drivers.

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